The well known closed rankine cycle comprises a boiler or evaporator for the evaporation of a motive fluid, a turbine fed with vapor from the boiler to drive the generator or other load, a condenser for condensing the exhaust vapors from the turbine, and the apparatus, such as a pump, for cycling the condensed fluid to the boiler. Such a system is shown and described in U.S. Pat. No. 3,393,515.
With the advent of the energy crisis, and the need to conserve and to more effectively use the available energies, rankine cycle systems have been used to capture the so called “waste heat” or the energy from naturally occurring sources such as methane gas flares or geo-thermal heat sources. A turbine as applied for this purpose is shown and described in U.S. Pat. No. 7,174,716 assigned to the assignee of the present invention.
In order to start such a refrigerant system, the oil used to lubricate the bearing of the turbine must be heated to bring the temperature above the point where refrigerant will condense and displace the oil. This has traditionally been accomplished by using a heater which is effective in maintaining the temperature once it has been achieved but takes a relatively long time to do so. It is therefore desirable to substantially reduce the time for starting up such an organic rankine cycle system and possibly eliminate the need for an oil heater.